The present invention is directed to a device for holding a part, which has a retainer member received in a receptacle member. The retainer member is provided for applying and holding the part and has a convexly spherical surface section and a surface section for the application of the part to be held, while the receptacle member provides a rotatable seating for the retainer member and comprises a concavely spherical surface forming al sliding seating surface for the convexly spherical surface section of the retainer member.
A device of this type is disclosed in German 196 02 636. The problem of plane-parallel alignment and adjustment of the two parts respectively comprising a planar surface section can be solved with such a device. This problem particularly occurs when the parts are to be permanently connected to one another after the adjustment, for example with laser welding, soldering or gluing.
For laser welding given the device disclosed by the German document, a laser beam serving this purpose can be supplied to the weld location for attachment of the part to be held unimpeded by the receptacle, the retainer member and the surface section as a result of a recess fashioned in the retainer member and the receptacle member.
When the surface sections of the parts to be connected to one another that face toward one another are aligned plane-parallel, a wedge-shaped gap, for example between these surface sections, leads to a warping when a weld or a solder hardens or when an adhesive cures. This warping generally modifies the relative position of the parts connected to one another in an unfavorable way.
An automatic, plane-parallel alignment is achieved with a device of this type in that one part is held on a rotatably seated retainer member of the device while the other part is firmly held outside the device.
For automatic alignment of the parts, the planar surface section of the part held on the retainer member and the planar surface section of the part firmly held outside the device are placed into contact with one another under a slight pressure.
Given proper dimensioning of the device, the two parts are aligned such that their planar surface sections facing toward one another are aligned plane-parallel relative to one another.
According to the above-mentioned German document, it is necessary for this purpose that the tilting or alignment moment generated by the pressing power is greater than the frictional moment of the convexly spherical surface section of the retainer member on the concavely spherical surface section of the receptacle member of the device forming the glide surface. With a given geometry of the device, the automatic alignment can only occur up to a maximum coefficient of friction and, thus, frictional moment as well.
The invention is based on the object of offering a device for holding a part for an automatic alignment of this part that produces an automatic alignment largely independently of the dimensioning and/or geometry of the device, even given slight pressing power.
According to the solution of the present invention, the inventive device comprises the features of an improvement in a device having a retainer member received in a receptacle member with the retainer member having a convexly spherical surface section and a surface section for applying the part to be held and the receptacle member providing a rotatable bearing for the retainer member, said rotatable bearing being a concavely spherical surface forming a glide seat surface for the convexly spherical surface section of the retainer member. The improvement comprises a glide means for arrangement between the concavely spherical surface section of the receptacle member and the convexly spherical surface section of the retainer member of the device, which accepts this section, the glide means being in the form of a glide layer.
As a result of the glide layer arranged between the concavely spherical surface section of the receptacle member and the convexly spherical surface section of the retainer member accepted in this section, the coefficient of friction between these two sections can be advantageously kept so slight that the dimensions and geometry of the device no longer have any influence on the pressing power or pressure needed for the alignment, and this pressing power can be extremely low.
A preferred and advantageous development of the inventive device comprises a means for at least temporarily producing the glide layer composed of the glide means between the concavely spherical surface section of the receptacle member and the convexly spherical surface section of the retainer member accepted therein.
In this case, one can advantageously proceed so that the glide layer is produced during the alignment event in order to keep the friction between the retainer member and the receptacle member as low as possible. After self-alignment has occurred, the glide layer can be eliminated for a secure fixing of the alignment and, thus, this friction can be, in turn, increased.
This can be especially simply implemented when the glide means is a gas, for example air.
In this case, it is advantageous in view of a simple structure when the means for producing the glide layer of the gas comprises at least one inflow opening fashioned in one of the two spherical surface sections, preferably an inflow opening fashioned in the surface section of the receptacle member for allowing a gas to flow in under pressure into the interspace between the two spherical surface sections.
The means for producing the glide layer of the gas can thereby comprise an optionally actuatable means for producing a gas under pressure, preferably arranged outside the retainer member and the receptacle member. This means is connected to the inflow opening, preferably by a channel fashioned in the receptacle member and leading to the inflow opening and a pressure conduit, which connects the channel to the means.
An air bearing of the retainer member, which advantageously enables a practically friction-free and, thus, resistance-free turning of the retainer member in all directions around a center of a sphere of the convexly spherical surface section, is realized by the glide layer of the pressurized gas formed between the convexly spherical surface section of the retainer member and the concavely spherical surface section of the receptacle member.
A better fixing of the alignment following the alignment event can be advantageously achieved by means of a temporary producing of an under-pressure between the two spherical surface sections for mutually pressing these two surface sections against one another. The retainer member and the receptacle member can thereby be advantageously firmly fixed relative to one another so that a modification of the alignment of the retainer member and, thus, of the part held on this member is practically only possible with the application of a force.
The means for temporarily producing an under-pressure between the two spherical surface sections can be constructed similar to a means for generating the pressure when the means for generating the under-pressure comprises at least one extraction opening formed in one of these two surface sections, preferably, the section of the receptacle member for removal of the gas in the interspace between the two spherical surface sections.
Similar to the means for generating the pressure, it is also advantageous here when the means for generating the under-pressure between the two spherical surface sections comprises an optionally actuatable means for generating the under-pressure, preferably arranged outside the retainer member and the receptacle member. The means is connected to an extraction opening, preferably by a channel fashioned in the receptacle member and leading to the extraction opening and an under-pressure conduit that connects the channel to this under-pressure generating means.
Advantageously, recesses are formed in the retainer member and the receptacle member, and the recesses allow at least two light beams directed onto the convexly spherical surface section in directions that are oblique relative to one another to emerge unimpeded through the receptacle and retainer member and from the surface section for application on the part to be held. When, in this case, laser beams for welding are employed as the light beams, two or more weld locations separate from one another can be simultaneously achieved. In this way, two parts to be aligned plane-parallel relative to one another and to be joined to one another can be simultaneously welded to one another at two or more separate points.
For holding a part on the device, a fastening tool for optionally releasable fastening of the part to be held on the retainer member is preferably secured on the retainer member.
Often, the part to be held is cylindrical, at least in sections thereof, and comprises a planar end face to be aligned plane-parallel with respect to another planar surface. In this case, the fastening tool is preferably a clamp tool having clamping jaws grouped around an axis and perpendicularly adjustable, for example adjustable radially relative to this axis, between which the part can be held with its cylindrical axis coaxially to the axis of the tool. The clamp tool is preferably secured on the retainer member so that the axis of the clamp tool coincides with an axis proceeding through the spherical center of the convexly spherical surface section of the retainer member.
For example, housings for holding optical lenses or fiber ends that are to be connected to optical transmitter modules via a planar end face of these modules are cylindrical, at least in sections. Given a housing for holding a fiber end, the fiber forming this end usually hangs from the housing in the form of a long fiber tail that, for example, can have a length of a few decimeters or more. This fiber tail can be a disturbing factor when fastening the housing to the retainer member.
This problem can be entirely or at least partially eliminated when a slot for the acceptance of the fiber is fashioned in the retainer member. The slot expediently extends in the direction of the cylindrical axis of the housing held on the retainer member, extending entirely through the retainer member in the direction perpendicular to this axis, but only partly, so that the retainer member remains together and does not fall apart. Since the retainer is arranged on the receptacle member and hardly any interspace is located between these members, it is expedient when a slot for the acceptance of the fiber is also fashioned in the receptacle member, and this slot is aligned with the slot of the retainer member.
An optional fastening and re-release of a part to be held in the fastening tool fastened on the retainer member can be advantageously achieved by a pneumatic means for an optional opening and closing of the fastening tool. Preferably and advantageously, such a means for optionally opening and closing the fastening tool is fashioned in the retainer member and is externally actuatable.
When, for example, the fastening tool is composed of a clamp tool having two or more adjustable clamping or clamp jaws, then the means arranged in the inside of the retainer member for optionally opening and closing the clamp tool can, per clamp jaw, comprise a respective hydraulic or, preferably, pneumatic cylinder and a force transmission means for the transmission of a piston force of the cylinder onto the clamp jaw for optionally opening said clamp jaw in the direction of a closing or opening of the clamp tool.
Each pneumatic cylinder is preferably connected, for example by a channel fashioned in the retainer member, to an inflow and outflow opening fashioned in the convexly spherical surface section of the retainer member. An inflow and outflow opening is arranged in the convexly spherical surface section of the receptacle member opposite the inflow and outflow opening, and the inflow and outflow opening is connected to a means preferably arranged outside the retainer and receptacle member for optionally generating a pressure and an under-pressure. Preferably, this means is connected by a channel formed in the receptacle member and leads to the inflow and outflow opening and by a pressure and under-pressure conduit connecting this channel to this means. The inflow and outflow opening fashioned in the concavely spherical surface section of the receptacle member preferably comprises a larger diameter than the inflow and outflow opening fashioned in the convexly spherical surface section of the retainer member. This has the advantage that a cylinder, even given a retainer member tilted relative to the receptacle member, can be actuated as long as the inflow and outflow openings of the tilted retainer member still lie in the region of the inflow and outflow openings of the receptacle member.
In any case, the means for an optional opening and closing of the fastening tool advantageously enables an actuation of the tool for fastening or releasing the part to be held, regardless of whether the retainer member happens to be movably seated on the receptacle member or happens to be fixed on the receptacle member.
Particularly given an employment of the inventive device for fastening a housing for holding an optical lens or a fiber end at an optical transmitter module, it is advantageous when an imaging optics and an optical detector are permanently arranged in the retainer member so that the imaging optics focuses light onto the detector. The light enters into this member through an opening fashioned in the surface section for applying the part of the retainer member to be held. As a result thereof, a pre-adjustment of the retainer member with respect to a light beam emitted by the module is enabled and the optical lens or fiber end in the housing can be adjusted thereto.
The imaging optics and the optical detector are preferably arranged on an axis of the retainer member proceeding through the spherical center of the convexly spherical surface section of the retainer member. In this case, the retainer member can be advantageously pre-adjusted relative to a light beam emitted by the module so that this axis of the retainer member coincides with an axis of the light beam. It is expedient to rigidly arrange the imaging optics and the optical detector in a preferably interchangeable fastening tool that is arranged coaxially relative to the axis of the retainer member and on which the housing with the lens or the fiber end is held coaxially relative to this axis.
The dimensions of the inventive device are largely arbitrary. In particular, a special advantage is to be seen wherein a radius of the surface sections of the retainer member cannot only lie in the millimeter range and below, but can also be larger than one centimeter, for example five centimeters.
An inventive device can be especially advantageously utilized for the parallel alignment of a planar surface section of the part relative to a planar surface section of another part facing toward this surface section. Thus, the one part is secured on the retainer member so that the planar surface section oft his part faces away from the retainer member and the receptacle member and wherein the planar surface section of the one part secured in this way and the planar surface of the other part are brought into planar contact with one another by moving the retainer member with the receptacle member and the other part relative to one another.
The planar surface sections of the one part secured on the retainer member and of the other part, that are brought into planar contact with one another, can be advantageously firmly joined to one another by laser welding. An optical lens and/or fiber mount can thereby be advantageously employed as the one part and an optical module, for example in the form of a laser module, to which the optical lens and/or the fiber mount is to be precisely coupled, can be employed as the other part.